Aenictus alticola

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Aenictus alticola
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dorylinae
Genus: Aenictus
Species: A. alticola
Binomial name
Aenictus alticola
Wheeler, W.M. & Chapman, 1930

Aenictus-alticolaL3.2x.jpg

Aenictus-alticolaD3.2x.jpg

Type Specimen Label

Nothing is known about the biology of this species.

Identification

A member of the laeviceps species group. Jaitrong and Yamane (2011) - A. alticola is most similar to Aenictus luzoni in having the subpetiolar process low and anteriorly angulate; the ventral appendage not spiniform. However, this species is distinctly larger than the latter (HW 0.80–0.85 in A. alticola; 0.78 in A. luzoni). The ventral appendage of the subpetiolar process is high and subtriangular in A. alticola, but rudimentary, with the highest point at anterior portion in A. luzoni. Antennal scape is almost as long as or longer than head width in A. alticola (SI 100–106), while it is shorter than head width in A. luzoni (SI 97).

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Philippines (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Abundance

Rare

Biology

Little is known about the biology of Aenictus alticola. The genus is comprised of species that live an army ant lifestyle. Aenictus typically prey on other ants, from other genera, or other insects such as wasps or termites. There are reports of Aenictus preying on other insects as well and even have been observed collecting honeydew from homopterans (Santschi, 1933; Gotwald, 1995) but this appears, at least from available evidence, to be uncommon. Foraging raids can occur day or night across the ground surface. Occasionally raids are arboreal. During a raid numerous workers attack a single nest or small area, with several workers coordinating their efforts to carry large prey items back to the nest or bivouac. Aenictus have a nomadic life style, alternating between a migratory phase in which nests are temporary bivouacs in sheltered places above the ground and a stationary phase where semi-permanent underground nests are formed. During the nomadic phase bivouacs move regularly, sometimes more than once a day when larvae require large amounts of food. Individual nests usually contain up to several thousand workers, although nest fragments containing only a few hundred workers are often encountered. Queens are highly specialised and look less like workers than in most ant species. They have greatly enlarged gasters (dichthadiform) and remain flightless throughout their life. New colonies are formed by the division of existing colonies (fission) rather than by individual queens starting colonies on their own.

Castes

Only known from the worker caste.

Wilson 1964 Army Ant fig 15-20

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • alticola. Aenictus (Typhlatta) alticola Wheeler, W.M. & Chapman, in Wheeler, W.M. 1930g: 205, fig. 5 (w.) PHILIPPINES. See also: Wilson, 1964a: 445; Jaitrong & Yamane, 2011: 24.

Description

Worker

Jaitrong and Yamane (2011) - Measurements. Worker lectotype and paralectotypes (n = 6): TL 4.35–4.75 mm; HL 0.90–1.00 mm; HW 0.80–0.85 mm; SL 0.78–0.88 mm; ML 1.43–1.50 mm; PL 0.30–0.35 mm; CI 84–87; SI 100–106.

Redescription (lectotype and paralectotypes). Head in full-face view clearly longer than broad, with sides slightly convex and posterior margin convex; occipital margin bearing a narrow collar. Antennal scape extending beyond midlength of head, but not reaching the posterolateral corner of head; antennal segments II–X each longer than broad; II slightly longer than each of III–VI; VII, VIII and IX combined almost as long as terminal segment (X). Frontal carina short, not reaching the level of the posterior margin of torulus. Parafrontal ridge short and ill defined, or absent. Anterior margin of clypeus convex and bearing 6–7 denticles. Masticatory margin of mandible with a large apical tooth followed by a medium-sized subapical tooth, 5–6 denticles, and a medium-sized basal tooth; basal margin sinuate with a series of 2–3 ill-defined denticles. Mesosoma rather elongate and stout; promesonotum in profile strongly convex dorsally and sloping to metanotal groove; metanotal groove very weak. Propodeal junction evenly rounded; declivity not margined dorsally and laterally. Petiole subsessile and short, its node almost as long as high and rounded dorsally; subpetiolar process well developed, triangular, its apex directed downward. Postpetiole shorter than petiole, with globular node.

Head entirely smooth and shiny. Mandible very finely striate except along masticatory and outer margins. Antennal scape almost smooth and shiny. Mososoma extensively smooth and shiny; upper portion of mesopleuron and metapleuron provided with about 10 longitudinal, irregular rugulae; dorsa of mesonotum and propodeum superficially sculptured; metanotal groove bearing short longitudinal rugulae; propodeal dorsum with several short longitudinal rugae in front of the junction. Petiole and postpetiole entirely smooth and shiny. Legs entirely smooth and shiny.

Head and mesosoma with relatively sparse standing hairs mixed with sparse short hairs over the surface; longest pronotal hair 0.20–0.25 mm long. Entire body reddish-brown except for vertex of head darker than other parts of body; ventral surface of antennal segments VII–X pale yellow. Typhlatta spot located anterior to occipital corner.

Type Material

Described from numerous workers taken by Dr. Chapman from a single large colony found raiding in Polis Pass, Bontoc, Luzon, at an altitude of 6,000 feet.

Jaitrong and Yamane (2011) - Twenty-one syntype workers on three pins (two on a pin, eight on another, eleven on the other) from Philippines, Luzon, Bontoc, Polis Pass, 1,800 m (Museum of Comparative Zoology, examined). One worker among them (top on the first pin) is selected as the lectotype, the others as paralectotypes. Collected by J.Chapman

References

  • Chapman, J. W.; Capco, S. R. 1951. Check list of the ants (Hymenoptera: Formicidae) of Asia. Monogr. Inst. Sci. Technol. Manila 1: 1-327 (page 12, checklist)
  • Jaitrong, W. & Yamane, S. 2011. Synopsis of Aenictus species groups and revision of the A. currax and A. laeviceps groups in the eastern Oriental, Indo-Australian, and Australasian regions (Hymenoptera: Formicidae: Aenictinae). Zootaxa, 3128, 1–46.
  • [1] Wheeler, W. M. 1930j. Philippine ants of the genus Aenictus with descriptions of the females of two species. J. N. Y. Entomol. Soc. 38: 193-212 (page 205, fig. 5 worker described)
  • [2] Wilson, E. O. 1964a. The true army ants of the Indo-Australian area (Hymenoptera: Formicidae: Dorylinae). Pac. Insects 6: 427-483 (page 445, see also)